 export function  base64toBlob(dataurl) {
     var arr = dataurl.split(','),
         mime = arr[0].match(/:(.*?);/)[1],
         bstr = atob(arr[1]),
         n = bstr.length,
         u8arr = new Uint8Array(n);
     while (n--) {
         u8arr[n] = bstr.charCodeAt(n);
     }
     return new Blob([u8arr], { type: mime });
 }